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DS: Fachverband Dünne Schichten

DS 13: Oxide Semiconductors for Novel Devices (Focussed Session): Session III

DS 13.2: Hauptvortrag

Dienstag, 13. März 2018, 10:00–10:30, E 020

Deep level defects in bulk and epi-grown β-Ga2O3 — •Lasse Vines — University of Oslo, Norway

After the early work on gallium oxide (Ga2O3) in the mid-1900s, a renewed interest has recently emerged on behalf of its prospects in power electronics and UV devices. Particularly, the monoclinic β-Ga2O3 phase attracts interest due to its band gap of ~ 4.8 eV and n-type conductivity, and where promising MOSFET devices have already been demonstrated. However, while controlling charge carrier and defect concentrations is essential for high power and high temperature devices, the understanding of the electrically active defects and dopants is still in its infancy. Here, the present status of controlling electrical properties of β-Ga2O3 will be reviewed, and recent progress in understanding electrically active defects and dopants will be discussed. In particular, recent results combining deep level transient spectroscopy with secondary ion mass spectrometry and ion irradiation on a range of different samples will be shown. The results reveal both intrinsic and extrinsic defects present in the samples, and give insight into the nature new and previously reported energy levels. For example, iron is shown to be an important impurity in bulk samples with an energy level position around 0.78 eV below the conduction band edge, acting as a deep compensating center, while irradiation demonstrate the appearance of a nearby intrinsic defect level, and the results are further supported by density functional calculations